package com.loong.framework.utils;

import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpSession;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.util.Random;
import javax.imageio.ImageIO;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author:zhanwang
 * @date: 2023/8/15
 * @time: 16:10
 */
@SuppressWarnings({"all"})
public class RandomValidateCodeUtil {

  public static final String RANDOM_CODE_KEY =
      "xxxCCRAND66YYOMVALIDATECODEKEYTenX011!@11///???"; // 放到session中的key
  private static final Logger logger = LoggerFactory.getLogger(RandomValidateCodeUtil.class);
  private final String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // 随机产生数字与字母组合的字符串

  private final int width = 95; // 图片宽
  private final int height = 25; // 图片高
  private final Random random = new Random();

  /** 获得字体 */
  private Font getFont() {
    return new Font("Fixed", Font.BOLD, 18);
  }

  /** 获得颜色 */
  private Color getRandColor(int fc, int bc) {
    if (fc > 255) fc = 255;
    if (bc > 255) bc = 255;
    int r = fc + random.nextInt(bc - fc - 16);
    int g = fc + random.nextInt(bc - fc - 14);
    int b = fc + random.nextInt(bc - fc - 18);
    return new Color(r, g, b);
  }

  /** 生成随机图片 */
  public void getRandomCode(HttpServletRequest request, HttpServletResponse response) {

    HttpSession session = request.getSession();

    // BufferedImage类是具有缓冲区的Image类,Image类是用于描述图像信息的类
    BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

    // 产生Image对象的Graphics对象,改对象可以在图像上进行各种绘制操作
    Graphics g = image.getGraphics();

    g.fillRect(0, 0, width, height); // 图片大小

    g.setFont(new Font("Times New Roman", Font.PLAIN, 18)); // 字体大小

    g.setColor(getRandColor(110, 133)); // 字体颜色

    // 绘制干扰线
    // 干扰线数量
    int lineSize = 40;
    for (int i = 0; i <= lineSize; i++) {
      drawLine(g);
    }

    // 绘制随机字符
    String randomString = "";

    // 随机产生字符数量
    int stringNum = 4;
    for (int i = 1; i <= stringNum; i++) {
      randomString = drawString(g, randomString, i);
    }

    // logger.info(randomString);

    // 将生成的随机字符串保存到session中
    session.removeAttribute(RANDOM_CODE_KEY);
    session.setAttribute(RANDOM_CODE_KEY, randomString);
    g.dispose();

    try {
      // 将内存中的图片通过流动形式输出到客户端
      ImageIO.write(image, "JPEG", response.getOutputStream());
    } catch (Exception e) {
      logger.error("将内存中的图片通过流动形式输出到客户端失败>>>>   ", e);
    }
  }

  /** 绘制字符串 */
  private String drawString(Graphics g, String randomString, int i) {
    g.setFont(getFont());
    g.setColor(new Color(random.nextInt(101), random.nextInt(111), random.nextInt(121)));
    String rand = String.valueOf(getRandomString(random.nextInt(randString.length())));
    randomString += rand;
    g.translate(random.nextInt(3), random.nextInt(3));
    g.drawString(rand, 13 * i, 16);
    return randomString;
  }

  /** 绘制干扰线 */
  private void drawLine(Graphics g) {

    int x = random.nextInt(width);
    int y = random.nextInt(height);

    int xl = random.nextInt(13);
    int yl = random.nextInt(15);

    g.drawLine(x, y, x + xl, y + yl);
  }

  /** 获取随机的字符 */
  public String getRandomString(int num) {
    return String.valueOf(randString.charAt(num));
  }
}
